In today's radio communications networks a number of different technologies are used, such as Long Term Evolution (LTE), LTE-Advanced, Wideband Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), or Ultra Mobile Broadband (UMB), just to mention a few possible implementations. A radio communications network comprises radio base stations providing radio coverage over at least one respective geographical area forming a cell. The cell definition may also incorporate frequency bands used for transmissions, which means that two different cells may cover the same geographical area but using different frequency bands. User equipments (UE) are served in the cells by the respective radio base station and are communicating with respective radio base station. The user equipments transmit data over an air or radio interface to the radio base stations in uplink (UL) transmissions and the radio base stations transmit data over an air or radio interface to the user equipments in downlink (DL) transmissions.
With the usage of Personal Computer (PC) cards, dongles and the heavy increase in smartphone penetration, the packet data traffic has more or less exploded in the radio communications networks. The mobile broadband traffic over the air interface is currently increasing considerably yearly. The mobile subscribers are using a large variety of services, most of them being Internet services going Over The Top (OTT) on a default bearer, i.e. OTT means that there is no agreement between the service provider and the operator for any specific treatment. Multi-tasking has become frequent, which means that the subscriber is using several services at a time at the user equipment, often multiple Internet services and some without end user intervention, e.g. status updates, emails, etc. during a video session. Being OTT services, without operator control, the services all share the same radio bearer through the Radio Access Network (RAN) to the user equipment, even though the services may have very different quality requirements to achieve a good end user experience.
Currently in the RAN all Quality of Service (QoS) adaptations are done per radio bearer, e.g. scheduling prioritization of data flows are done per radio bearer. RAN functions like Active Queue Management (AQM) and Explicit Congestion Notification (ECN) are thus applied per radio bearer. Statistics for observability purposes are also collected per radio bearer in the RAN.
When an end-user of a user equipment initiates a packet data session accessing the radio communications network a connection is setup between a core network and the user equipment commonly denoted as one bearer service. Several packet data sessions, or service data flows, may be carried by the same bearer service. The bearer service uniquely identifies packet flows, also referred to herein as service data flows, that receive a common QoS treatment between the user equipment and a gateway to the core network, i.e. through the RAN. In e.g. a System Architecture Evolution (SAE)/LTE radio communications network a corresponding bearer service is denoted Evolved Packet System (EPS) Bearer, while in Universal Mobile Telecommunications System (UMTS) a bearer service is defined by a Packet Data Protocol (PDP) Context.
Through the LTE RAN, each bearer service is associated with one E-UTRAN Radio Access Bearer (E-RAB), or for WCDMA RAN, a Radio Access Bearer (RAB), which is associated with one radio bearer. Radio bearer is herein used as a general term for a bearer through the RAN and comprises a radio access bearer, a bearer, or similar. For each radio bearer the same QoS is defined as for the bearer service. All traffic mapped to the same radio bearer receive the same treatment for packet forwarding on a bearer level e.g. scheduling policy, queue management policy, rate shaping policy, Radio Link Control (RLC) configuration. An EPS bearer or PDP Context is mapped to one logical channel, a radio bearer, or a radio access bearer for the different standards, e.g. E-RAB for LTE.
A core network node, e.g. a gateway node, may intercept traffic to perform packet inspection such as Deep Packet Inspection (DPI), flow identification, flow classification or similar, to detect different service data flows. The core network node may then initiate the setup of additional radio bearers in order to separate the different service data flows and to make it possible to differentiate the different service data flows on a service level by assigning different QoS to the different radio bearers based on the service of the different service data flows. But from a RAN perspective there is no guarantee that the process to separate the different service data flows on a radio bearer level actually is done in the core network. A drawback in e.g. WCDMA with the above core network solution is that it requires multiple radio bearers to be set up, which may introduce extra delay when setting up radio bearers in the radio communications network where the setup of radio bearers may be done in sequence. There are also limitations in the number of bearer combinations and number of parallel radio bearers supported by the user equipments and the radio communications network. This results in a reduced performance of the radio communications network.
Thus, the same packet forwarding treatment applies to all packets on a radio bearer even though they may belong to different services and thus have different quality requirements. RAN functions like AQM and ECN is thus applied per bearer and not per service. Statistics for observability purposes are also collected per bearer in RAN.
To allow RAN to differentiate between service flows within a bearer, a pre-scheduler may be introduced in the RAN that schedules data from different service data flows within the same radio access bearer. By doing that there will be two levels of scheduling, the pre-scheduler and the radio scheduler, or scheduler, within RAN and without correlation between the schedulers the wanted quality of service with respect to prioritization and delay requirements is not met. WO 2011/100914 relates to a pre-scheduler of a two layered scheduling mechanism that base the scheduling on priority of the pre-scheduling queues. However, this pre-scheduling results in a solution that queues the packets twice which may lead to a non-optimal service performance for e.g. delay sensitive services in the radio communications network.